Aerosol containers and valves thereof

ABSTRACT

THE DISCLOSURE ILLUSTRATES A VALVE WHICH MAY BE USED FOR THE AUTOMATIC OR MANUAL ACTUATION OF A DISPENSER FOR PRESSURIZED FLUIDS. THE VALVE INCORPORATES A PERMEABLE MEMBRANE, FOR EXAMPLE A LOW DENSITY POLYETHYLENE FILM, WHICH ALLOWS VAPOR FROM THE DISPENSER TO PERMEATE INTO THE VALVE AND GIVE RISE TO A PRESSURE BUILD-UP UNDER A SEALED DIAPHRAGM. THE PRESSURE BILD-UP EVENTUALLY CAUSES THE DIPHRAGM TO RELEASE A SPRING MECHANISM TO ACTUATE THE SPRAY OR AEROSOL DISCHARGE. ONCE DISCHARGE IS COMPLETE THE VAPOR UNDER THE DIAPHRAGM IS DISCHARGED AND THE MECHANISM AUTOMATICALLY RESET TO START THE CYCLE AGAIN.

May 23, 1972 R. w. BRODERICK AEROSOL CONTAINERS AND VALVES THEREOF m Sor a .3 Fl/ 04/ 8? Wm G i 2 m 4 0 J 6 i M N "III 0 7 \\N w 9, w M u J d9 1 m y 23, 1972 R. w. BRODERICK 3,664,548

AEROSOL CONTAINERS AND VALVES THEREOF Filed July 9, 1970 r 5Sheets-Sheet 3 lnvenlar Kw! wefionmu By I AGE/VT May 23, 1972 R. w.BRODERICK AEROSOL CONTAINERS AND VALVES THEREOF L5 Shoctu-l311eut 41Filed July 9, 1970 mam Eur

lnoenlor R RY W. BRUDERICR v 6 a 6 4 ml 3 5 0 r 1/ 5 Z 8 4. 0/ 2 m m B AMay 23, 1972 R. w. BRODERICK AEROSOL CONTAINERS AND VALVES THEREOF FiledJuly 9, 1970 IZE/I 56 United States Patent Oflice" 3,664,548 PatentedMay 23, 1972 3,664,548 AEROSOL CONTAINERS AND VALVES THEREOF Rory WilsonBroderick, Dalkey, Ireland, assignor to Institute for IndustrialResearch and Standards, and Norman John Thompson, both of Dublin,Ireland Filed July 9, 1970, Ser. No. 53,591

Claims priority, application Ireland, July 10, 1969,

941/69 Int. Cl. B67d 5 08 U.S. Cl. 22261 .24 Claims ABSTRACT OF THEDISCLOSURE The disclosure illustrates a valve which may be used for theautomatic or manual actuation of a dispenser for pressurised fluids. Thevalve incorporates a permeable membrane, for example a low densitypolyethylene film, which allows vapour from the dispenser to permeateinto the valve and give rise to a pressure build-up under a sealeddiaphragm. The pressure build-up eventually causes the diaphragm torelease a spring mechanism to actuate the spray or aerosol discharge.Once discharge is complete the vapour under the diaphragm is dischargedand the mechanism automatically reset to start the cycle again.

The present invention relates to aerosol containers and particularly tovalves for use in said containers. The term aerosol containers isintended to refer to enclosed containers charged with a fluid underpressure that is adapted to be expelled from the container by thepressure therein or more briefly a dispenser for pressurised fluids; AConventional aerosol containers are normally provided with a valveoperable by finger pressure to open the valve and thereby enable fluidin the container to issue to atmosphere. A demand exists, however, foraerosol contermittently operating the valve to permit periodic emissionof fluid from the aerosol container.

With a view to avoiding the expense involved in providing mechanicallyor electro-mechanically operable means for dispensing fluid from aerosolcontainers, a primary object of the present invention is to provide, foruse in such a dispenser for pressurised fluids, a valve which ismanually operable and which is operable automatically to dispense atregular intervals of time, a quantity of fluid from the dispenser. 1

According to the invention, there is provided a valve for a dispenserfor pressurised fluids, said valve comprising a valve housingincorporating a permeable membrane and pressure responsive means, thepermeable membrane which allows vapour under pressure in the dispenserto penetrate into the valve housing to build-up pressure in the valvehousing, the said built-up pressure actuating the pressure responsivemeans in the valve housing to open the valve, to discharge throughthevalve, pressurised fluid from the dispenser.

. Advantageously, the permeable membrane'which enables vapour to enterthe valve housing from the interior of the dispenser, permits a build-upof pressurein the valve housing over a time period substantially inexcess means serves to open the valve to enable a quantity of fluid todischarge from the dispenser. The process of penetrationof vapourthrough the permeable membrane is generally thought to be a solution orabsorption of vapour on the surface of the membrane followed bydiffusion of the vapour through the membrane. The vapour penetrationrate is approximately inversely related to the thickness of membraneused and also approximately linearily related to the pressure differenceacross the membrane. Thus for example the time period of the automaticcycle may readily be controlled by merely varying the thickness ofmembrane used.

In a preferred construction according to the invention, the valvecomprises:

(a) A bottom enclosure adapted to hold in sealed engagement a permeablemembrane and to house a sealing cup within a metering chamber which isconnected by a dip tube to the pressurised fluid in the dispenser.

(b) A mounting cup adapted at one end for fluid tight mounting on thedispenser the other end of the mounting cup engaging the bottomenclosure, housing a capillary stem seated, at one end thereof, in thesealing cup and pressure responsive means (c) An actuator which projectsto atmosphere from the mounting cup and contains a spray button with anorifice open to atmosphere, the orifice being connected to the capillarystem at that end thereof remote from the metering chamber.

The pressure responsive means utilised may to advantage comprise aflexible diaphragm mounted above a core, a cradle member, a snap springmounted on the cradle member, a collar fixedly mounted on the capillarystem and a cradle return spring, whereby a build-up of pressure due tothe pressurised vapour penetrating into the valve housing causes theflexible diaphragm to move away from thecore above which his mounted andforce the cradle to move in the same axial direction, until the snapspring isactuatedto depress the collar and hence the capillary stem andthe sealing cup to open the valve to dispense the pressurisjed fiuid inthe metering chamber to. atmosphere and allow dischargeof thepressurised fluid which has penetrated into the valve housing toatmosphere. I

Preferably the permeable membrane is a polyethylene film, thoughethylene vinyl acetate film, polytetrafluorethylene and fluorosiliconerubber have also-been found to be most suitable.

The invention will be more clearly understood from the followingdescription of preferred embodiments of the invention given by way ofexample only with reference to the accompanying drawings in which FIG. 1isan elevation in section of a valve in the closed position thereof,with the valve set for automatic operation FIG. 2 is an elevationsimilar to FIG. 1 but showing the valve in the open or spray dischargeposition FIG. 3 is a plan view of the valve FIG. 4 is an elevationsimilar to FIG. 1 showing the valve in a closed position and set formanual actuation FIG. 5 is an elevation in section of a modifiedconstruction of valve, the valve beingvshown in the closed position 'andset for automatic operation.

of the time period during which the pressure responsive Referring toFIGS. 1-4 of the drawings, the constructionof the valve is described forthe sake of clarity from its lower end, in its normal position of use,as shown in the drawings.

A-membrane sealing cap 10 having vertical slits in its sides 'to allowthe sides to-fiex during the assembly operation, is snap fitted on tothe bottom enclosure 11. The sealing cap 10 compresses a pair of O ringrubber seals 12 whichseal the periphery of a permeable membrane 13,

for example a low density polyethylene film, located .between thesealing cap and the bottom enclosure 11. A channel 11a, allows thepressurised vapour in the dispenser access to the permeable membrane 13.A disc of porous paper 14 lies between the permeable membrane 13 and thebottom of the bottom enclosure 11. A clip tube 15 is push fitted into anopening 16 in the side of the bottom enclosure 11 and the opening 16communicates via a bore 17 and via an inlet port 21, with a meteringchamber 18 within the bottom enclosure 11. The metering chamber 18 isprovided with a spring loaded sealing cup 19 which normally engagesunder the action of spring a rubber seal 20 positioned at the top of themetering chamber 18. The bore 17 from the dip tube 15 to this meteringchamber 18 terminates in the bottom of the metering chamber 18 in theinlet port 21 which is provided with a raised ridge 22. This ridge 22allows a rubber ferrule seal 23 on the sealing cup 19 to seal olf thisinlet port 21 when the sealing cup 19 is pressed downwards against it.

A plastic core 26 is located in the bottom enclosure 11, above themetering chamber 18. The core 26 is held in the bottom enclosure 11 byscrew threads 27 or alternatively, it may be ultrasonically welded intoplace. With either assembly method, the core 26 compresses the peripheryof the rubber seal 20 above the metering chamber 18 and ensures that therubber seal 20 prevents the leakage of fluid (vapour or liquid) from themetering chamber 18 into a timing chamber 28, which issubstantiallyfilled by the plastic core 26, and is beneath a flexiblerubber diaphragm 29. An annular valve seat 30 projects down from arecess provided in the bottom face of the core 26. The rubber seal 20above the metering chamber 18 is normally pressed against this seat byan upwards spring influenced thrust of the sealing cup 19 in themetering chamber 18. During the automatic cycle of the valve, thepressure of the contents of the metering chamber 18 also press therubber seal 20 against this valve seat 30, as the pressure in themetering chamber 18 is the same as the dispenser contents pressure(except when the chamber is emptied and the valve is resetting) and thepressure above the rubber seal 20 is considerably lower.

The flexible rubber diaphragm 29 is fastened above the top of the core26 by a hollow rivet 31. The rivet 31 passes through a hole in thecentre of the diaphragm 29 and is a tight fit in a hole in the core 26.The head 31a of the rivet 31 compresses a bead 32, which is around theedge of the hole in the diaphragm29 against a ridge 33 formed in thecore 26 and thereby creates a permanent seal here. The outer edge of thediaphragm 29 also contains a thickened bead 34 and this bead iscompressed against a ledge 35 in a valve mounting cup 36, by a raisededge 37 on the top of the bottom enclosure 11. The bottom edge 39 of thevalve mounting cup 36, a deep drawn metal component, is crimped induring assembly, under a step 38 in the outside wall of the bottomenclosure 11, to hold the bottom enclosure 11 in this position. Thiscreates a permanent seal at the peripheral edge of the diaphragm 29which serves two purposes, namely:

(a) To prevent the container contents fromleaking upwards past the ledgein the valve mounting cup and (b) To contain vapour, which has permeatedinto the,

space under the diaphragm.

From the foregoing, it may be seen that the timingchamber 28 is normallysealed from the atmosphere and also always sealed from the dispensercontents, except for the slow permeation of vapour through the membrane13.

Within this timing chamber 28 vapour flow paths or channels are providedon the bottom and sides of the core 26 to ensure that permeated vapour,rising through a vertical hole 40 from the membrane 13, may readily flowto the timing chamber 28 which is on the underside of the diaphragm 29.These channels also allow the flow of this vapour to the core recess 26awhere the annular valve seat 30 is located. 1

A hollow capillary stem 41 extends from the top of the valve, downthrough the pressure responsive means and the timing chamber 28 into themetering chamber 18.,A spray button 42 is located on the top of thisstem 41 and the spray button 42 is provided with an exit orifice 43 forthe discharge spray. The stem 41 is free to slide in the parts throughwhich it runs and the bottom of the stern rests in a well 19a providedwith an orifice groove 45, in the sealing cup 19. A collar 46, which isa tight fit, is located around portion of the stem 41.

In the top half of the valve mounting cup 36 above the diaphragm 29there is located a pressure responsive mechanism. The pressureresponsive means consists of a snap spring 48, a cradle 49, a cradlering 50, a helical return spring 51, an automatic-manual actuator 53 anda cover 54. The snap spring 48 is a flat strip of spring steel whichbows up when inserted into the cradle 49. The cradle contains locatingslots to orient the snap spring 48 and the slots 55 are tapered to allowflexing of the ends of the snap spring 48. The slots 55 run aroundportion of opposite sides of the cradle 49 and are slightly wider thanthe snap spring 48. The narrowest part of the slots 55 open to theoutside wall of the cradle 49 and thus ensure that the end-thrust of thesnap spring 48 is taken by a steel cradle ring 50 which is pressed overthe cradle 49. The bottom of the cradle 49 rests on the diaphragm 29 andit is pressed against the diaphragm 29 by the helical return spring 51.Two opposite portions of the bottom coil of this return spring 51 reston two opposite ledges 56 formed on the inside face of the cradle 49.

The top of the helical return spring 51 presses the automatic-manualactuator 53 upwards against the cover 54 of the valve. Two raised ribs57 are provided on the face of the actuator 53 which is close to the topinside face of the valve cover 54. When the actuator is in the automaticposition, these ribs rest in two shallow grooves 58 provided in the topinside face of the valve cover 54. When the actuator 53 is in the manualposition, the raised ribs 57 nest inside two slots 59 provided in thetop of the valve cover 54. The slots 59 are shown in the plan view ofthe valve FIG. 3. The rotation of the actuator 53 from the automatic tothe manual position thus has the eflect of retracting upwards by apredetermined amount, a finger 60 which has projected downwards from theactuator 56 into close proximity with the centre of the snap spring 48for automatic operation of the valve.

The sides of the valve mounting cup 36 are crimped in at 61 to hold thevalve cover 54 in place. The bottom edge 62 of the valve cover 54 actsas a cradle stop to limit upwards movement of the cradle 49. I

The valve may be operated manually by finger tip pres sure to giveeither:

(l) A continuous spray which is obtained by exerting slight fingerpressure on the spray button or (2) A metered spray which is obtained byexerting a greater finger pressure on the spray button.

Both of these modes of manual spraying may be obtained with theautomatic-manual actuator set in either the automatic or manualposition. Detailed working is as follows:

(1) Continuous spray-Downward movement of the spray button 42 causes thecapillary stem 41 to push the sealing cup 19 away from the rubber seal20, against which the sealing cup 19 has been pressed by the action ofthe spring 25. The seal formed between the lip on the top of the sealingcup 19 and the rubber seal 20 is thus opened and this allows the productpropellant mixture to flow from the metering chamber 18 into the well1901 in the sealing cup 19 and from there, via the orifice groove 45 inthe well 190, into the capillary stem 41 to emanate as a spray from thespray button orifice 43. If no further downward motion of the spraybutton 42 takes place, there will be a continuous flow of fluid into themetering chamber 18 from the dip tube 15, to maintain it full, so,

long as some pressurised contents remain in the disis applied initiallyto the spray button 42 and this causes the sealing cup 19 to open asbefore but also ensures that the ferrule seal 23 closes off the inletport 21 into Automatic operation FIG. 1 shows the valve parts in theirposition at the start of the automatic cycle. The bottom enclosure 11 ofthe valve, which houses the permeable membrane 13 may be below theliquid level of the product/propellant mixture in the dispenser if thecontainer is relatively full, or alternatively if the dispenser contentshave been partially used, the membrane 13 may be above the liquid leveland in the vapour phase alone. The liquid level in the dispenser dosenot alfect the functioning of the valve. It may be assumed that thevapour pressure under the diaphragm 29, atvthe commencement ofthe-cycleis at atmospheric. The pressure of the propellant in thedispenser is above atmospheric pressure and typically will be about 4 toatmospheres. Because of this pressure difference, propellant vapour,from either the liquid or vapour phase, gradually permeates through thepermeable membrane 13. The porous paper backing 14 under the membrane 13allows sideways transmission of this vapour to the vertical hole 40 inthe bottom enclosure 11 which communicates with the timing chamber 28under the diaphragm 29. The timing chamber 28 is partially occupied bythe core 26 and since the timing chamber 28 is sealed from theatmosphere, the pressure will gradually rise in the chamber 28 with aconsequent extension upwards of the diaphragm 29. This causes the cradle49 to move gradually upwards against the restrainingaction of the returnspring 51 and the snap spring 48. The finger 60 projecting down from theautomatic-manual actuator 53 limits the upward movement of the centre ofthe snap spring 48. When the edges of the snap spring 48, held in thecradle 49, reach a point level with or slightly above the bottom of thefinger 60 the snap spring 48 snaps over-centre. As the bottom edge 62 of.the cover 54 acts as a cradle stop further upward movement of thecradle 49 is only possible to a marginal extenL Thus the snap spring 48reacts downwards on the collar 46 of the capillary stem 41 and depressesthe capillarystem 41 and sealing cup 19.

FIG. 2 shows the position of the valve parts during this dischargeportion of the automatic cycle;- -As the inlet port 21 in the bottom ofthe metering chamber 18 has been closed by the ferrule seal 23, theproduct/propellant mixture, isolated in the meteringchamber' 18, willissue as a spray from the spraybutton orifice 43.

The emptying of the metering chamber 18 causes a resultant drop inpressure in it. The propellant'vapour under the diaphragm 29 is incommunication with the core recess 26a above the'rubber seal 20 which isabove the metering chamber 18 The resultant pressure dilference acrossthis seal ,29 causes it to deflect downwards slightly into the meteringchamber 18 and thereby move away from the annular valve seat 30 in thecore'26. The deformation of this seal 20, as shown in FIG. 2, allows thevapour, trapped under the diaphragm 29 to escape to atmosphere. Its pathin doing so follows a small channelv the capillary stem "41 and theholes of the parts throughwhich'the' stem slides. The cradle 49,presseddown by the return spring 5, forces the diaphragm 29 to deflateand expel the vapour. As the cradle 49 moves down during this deflationof the diaphragm 29, the snap spring 48 reacts against the collar 46 onthe capillary stem 41 which forcesthe snap spring 48 to subsequentlysnap back .over centre? into its original position. This allows thesealing 'cup 19 to move up in the metering chamber 18 again to itsoriginal position of sealing against the rubber seal 20 above meteringchamber 18. The automatic cycle will now commence again.

The automatic-manual actuator 53 projects upwards through the cover 54of the valve and partially surrounds the spray button 42. An opening 47in the side of the actuator 53 provides clearance for the spray from theexit orifice 43 of the spray button 42. The spray button 42 projectsabove the top of the actuator 53 to allow finger pressure to be appliedto the button 42 for manual spraymg.

As previously mentioned a finger 60 projects down into the valve fromthe actuator 53 and this finger 60, in the automatic mode of the valve,serves to compress the snap spring 48 during upward movement of thecradle 49, and thus causes the snap spring 48 to snap over to the downposition. Retraction upwards of the actuator 53 and finger '60 to theposition shown in FIG. 4 switches the valve from the automatic to themanual mode. Upwards movement of the cradle 49 with the actuator 53 inthis position does not now impose compression on the snap spring 48 andhence it will remain in the up position.

From the users point of view, the valve is switched from the automaticto the manual mode as follows: A metered spray is first dispensed bymanual pressure on the spray button 42. The auto-manual actuator 53 isthen grasped between the fingers, pressed down slightly and rotated aquarter turn to the manual position where it is released as it clicksinto position. The same procedure is followed to revert to the automaticposition.

The. initial manual spraying of a metered burst is necessary beforeturning the auto-manual actuator 53 as this serves to reset the cradle49 to the position it normally has at the start of the automatic cycle.In this position the snap spring 48 is not reacting against the finger60.of the actuator 53 .and the upwards force of the cradle returnspring. 51 against the actuator 53 is at a minimum. Thus the actuator 53can be easily depressed 1 y and rotated.

The switching of the actuator 53 from the automatic to-the manualposition does not immediately stop penetration of vapour through thepermeable membrane 13. Penetration of vapour continues for some time andwill cease only when'the vapour pressure under the disphragm 29hasreached equilibrium with the pressure in the dispenser. FIG. 4 showsthevalve in this manual position and this would normally be the positionof the parts during storage of the dispenser (aerosol container) prior-1 to sale or use.

A second embodiment of the invention is illustrated in- FIG. 5 of theaccompanying drawings. In FIG. 5 like valve parts to those shown inFIGS. 1-4 illustrating the first embodiment, are given the samereference numeral, proceeded by the digit one, for the sake of clarity.In

this second embodiment the permeable membrane geometry has been alteredand the form of the cradle return spring varied. The valve operateshowever in substantially the same manner as described in relation to thefirst embodiment.

The disc type of permeable membrane as illustrated in FIGS. 1, 2 and 4of the accompanying drawings must be limited in area, if the valve is tofit into the standard one lIlCh opening of dispensers for pressurisedfluids (aerosols). Accordingly, in applications of the valve where afairly frequent intermittent spray is required, a different geometry ofpermeable membrane may be adopted to allow a larger effective area ofpermeable membrane for vapour penetration. The cylindrical type ofpermeable membrane shown in FIG. covers this requirement. Here thecylindrical permeable membrane 113, in the form of a length of tubularlow density polyethylene film, is heat shrunk or slipped as a tight fitover the exterior surface of the bottom enclosure 111. If the bottomenclosure 111 has been manufactured from a compatible plastic material,the two ends of the cylindrical permeable membrane 113 may be heatsealed or bonded with an adhesive to the exterior cylindrical surface ofthis bottom enclosure 111 to form hermetic joints in these areas. Asleeve of porous paper 114 is interposed between the cylindricalpermeable membrane 113 and the bottom enclosure 111, except in the areaat the ends where the sealing takes place. This sleeve of. porous paper114 lies in a shallow groove formed on the exterior cylindrical surfaceof the bottom closure 111. The porous paper 114 allows transmission ofvapour, which has penetrated through the membrane 113, to a hole whichcommunicates with the timing chamber 128.

With this form of construction, a very large area of permeable membrane113 can be obtained readily. It also allows the more conventional bottomentry of the dip tube 115 into the valve.

FIG. 5 also illustrates an alternative geometry for the cradle returnspring 151. Here a stack of disc springs have been substituted for thehelical spring shown in the FIGS. 1, 2 and 4 of the accompanyingdrawings. These disc springs 151 may be full discs or alternatively mayhave radial cut outs so that each disc has a number of fingersprojecting either radially inwards from a solid periphery or radiallyoutwards from the centre portion of the disc. The springs 151 may bemanufactured from conventional spring materials such as stainless steelor spring steel or alternatively may be manufactured from a bimetalspring material.

In some applications of the valve, the use of a bimetal material heremay be necessary, in order to reduce the variation in frequency withtemperature of the automatic intermittent operation. The pressure in adispenser container normally increases with a rise in the ambienttemperature, because of the properties of the propellant fluid. Thisresults in a more rapid penetration of vapour through the membrane 113and, with the valve construction shown previously, a faster automaticcycle. This m'ay be an advantage in both insecticidal and airfreshe'ning applications, where higher temperatures normally result inmore insects or more odours. In other applications, however, such as theautomatic lubrication of machinery, a dispensing frequency which isrelatively independent of ambient temperature may be required. In suchan application, the disc springs 151 may be made of bimetal springmaterial, so arranged that the thrust of the springs 151 against thesnap spring cradle 149 increases with temperature. A higher pressureunder the diaphragm 129 is thus required to operate the valve and this,compensating for the higher pressure in the can, results in a relativelyuniform automatic dispensing frequency.

What we claim is:

1. A valve for a dispenser for pressurized fluid, said valve comprisinga valve housing incorporating a permeable membrane, a timing chamber incommunication with the permeable membrane, pressure responsive means, anexit orifice, a fluid supply under pressure, and

a valve disposed intermittent the exit orifice and fluid supply, saidpermeable membrane allowing vapor under pressure in the dispenser topenetrate by diffusion into the valve housing along one path to build-uppressure in the timing chamber, said timing chamber being enclosed atleast 'in part by a flexible diaphragm which can move in response to thebuild-up of pressure to actuate the pressure responsive means to openthe valve and discharge fluid under pressure through a second path byway of the valve and exit orifice.

2. The valve of claim 1 wherein the pressure responsive means includes asnap spring which in response to 8 the build-up of pressure in thetiming chamber can snap over from a first position to a second positionto open the valve.

3. The valve of claim 1 includes a metering chamber within said secondpath, a closable inlet thereto in communication with the interior of thedispenser, a closable outlet therefrom in communication with atmosphere,and means for holding said inlet closed while said outlet is open, andvice versa. V

4. The valve of claim 1 wherein there is included:

(a) a bottom enclosure adapted to hold in sealed engagement thepermeable membrane and to house a sealing cup within a metering chamberwhich is connected by a dip tube to the pressurized fluid in thedispenser;-

(b) a mounting cup adapted at one end for fluid tight mounting on thedispenser, the other end of the mounting cup engaging the bottomenclosure '(a), housing a capillary stem seated, at one end thereof, inthe sealing cup and pressure responsive means; and

'(c) an actuator which projects to atmosphere from the mounting cup andcontains a spray button with the orifice exit to the atmosphere, theorifice exit being connected to the capillary stem at that end thereofremote from the metering chamber.

5. A valve for a dispenser for pressurized fluids, said valvecomprising:

(a) a bottom enclosure adapted to hold in sealed engagement a permeablemembrane and to house a sealing cup within a metering chamber which isconnected by a dip tube to the pressurized fluid in the dispenser;

(b) a seal member located between the sealing cup and the core, saidseal member in co-operation with the sealing cup and the core beingadapted to prevent vapor passing along the exterior and/ or interior ofthe capillary stem between the metering chamber and atmosphere and alongthe exterior of the capillary stem between the timing chamber andatmosphere when the valve is closed, the said sealmember being adaptedto deform following discharge of the contents of the metering chamber toallow the vapor in the timing chamber, which has built up a pressureunder the flexible diaphragm, to discharge to atmosphere, closing of thevalve serving to allow the seal member reverse to its undeformed sealingposition;

(c) a mounting cup adapted at one end for fluid tight mounting on thedispenser, the other' end of the mounting cup engaging the bottomenclosure, housing a capillary stem seated, at one end thereof, in

, the sealing cup and pressure responsive means; and

(d) an actuator which projectsto atmosphere from the mounting cup andcontains a spray button with an orifice open to atmosphere, the orificebeing connected .to the capillary stem at that end thereof remote fromthe metering chamber.

6. A valve as claimed in claim 3 which includes means 0 responsive tothe evacuation of pressurised fluid from the metering chamber forreleasing the pressure in the' timingvchamber and means responsive tothe release of pressure from the timing chamber for closing the valve:

7. A valve as claimed in claim 6 wherein the means for closing the valveserve to close the outlet from the meable membrane is fiurosiliconrubber.

12. A valve as claimed in claim in which the bottom enclosure isprovided with a membrane sealing cap which is snap fitted to the bottomenclosure to compress sealing members to seal in position a permeablemembrane mounted upon the bottom enclosure, the membrane sealing caphaving a channel therein to provide an access for the pressurised vapourin the dispenser to the permeable membrane.

13. A valve as claimed in claim 5 in which the permeable membrane ismounted upon a portion of the exterior surface of the bottom enclosureand heat sealed at its edges to the bottom enclosure.

14. A valve as claimed in claim 12 in which a layer of porous paper isprovided between the permeable membrane and the bottom enclosure, thebottom enclosure having a communicating passage therein to allow thepressurised vapour penetrating the permeable membrane to pass to atiming chamber immediately adjacent a flexible diaphragm on a core sidethereof.

15. A valve as claimed in claim 5 in which the bottom enclosure isprovided with a metering chamber which houses a spring mounted sealingcup, the bottom of the metering chamber being provided with an inletport connected to the dip tube, the sealing cup having mounted thereon aseal member which closes the inlet port when the sealing cup isdepressed upon the opening of the valve.

16. A valve as claimed in claim 5 in which the sealing cup is providedwith a well having an orifice groove which communicates with the end ofthe capillary stem within the well for discharge to atmosphere of thecontents of the metering chamber when the valve is open.

17. A valve -for a dispenser for pressurised fluids as claimed in claim5 in which the pressure responsive means comprises a flexible diaphragmmounted above the core, a cradle member, a snap spring mounted on thecradle member, a collar fixedly mounted on the capillary stem and acradle return spring, whereby a build-up of pressure due to thepressurised vapour penetrating into the valve housing causes theflexible diaphragm to move away from the core above which it is mountedand "force the cradle to move in the same axial direction, until thesnap spring is actuated to depress the collar and hence the capillarystem and the sealing cup to open the valve to dispense the pressurisedfluid in the metering chamber to atmosphere and allow discharge of thepressurised 10 vapour which has penetrated into the valve housing toatmosphere.

18. A valve as claimed in claim 17 in which the flexible diaphragm is ofrubber and is sealed on the bottom enclosure at its outer edge portionsby the mounting cup and at its centre by a rivet mounted about thecapillary stem.

19. A valve as claimed in claim 17 in which the snap spring of thepressure responsive means is a strip spring which bows when mounted inlocating slots provided in the cradle said slots being adapted to locateand accommodate the end edge portions of the snap spring and to allowcomplete flexin g of the snap spring.

20. A valve as claimed in claim 17 in which the cradle of the pressureresponsive means is provided with a cradle ring to provide a suitablebearing surface for the end edges of the snap spring.

21. A valve as claimed in claim 17 in which the cradle return spring isa helical spring mounted around the capillary stem and between thecradle and the actuator.

22. A valve as claimed in claim 17 in which the cradle return spring isa stack of disc springs of bimetal material responsive to a variation intemperature.

23.'A valve as claimed in claim 17 in which the actuator is providedwith a finger which embraces the capillary stem and which is constrainedfor limited axial movement relative to the capillary stem for setting ofthe valve for automatic or manual operation, the flnger almost abuttingagainst the snap spring when the valve is set for automatic operationand in an axially retracted position from the snap spring when the valveis set for manual operation.

24. A valve as claimed in claim 23 in which the actuator is providedwith a cover fixedly mounted on the mounting cup and adapted toco-operate, by means of a complimentary rib and groove arrangement, withthe actuator for setting of the valve for automatic or manual operation.

References Cited UNITED STATES PATENTS 3,115,277 12/1963 Montague, 1a.,222- UX 3,497,108 2/ 1970 Mason 222-499 ROBERT B. REEVES, PrimaryExaminer J. M. SLATIERY, Assistant Examiner

